Red wine drinkers have better gut health, say researchers

People who drink red wine are more likely to have a more diverse gut microbiota compared to non-red wine drinkers, according to a new King's College London study involving 916 twins.

The findings, published in the journal Gastroenterology,​ also suggest a link between red wine drinking and lower levels of obesity and 'bad' cholesterol.

The team of researchers from the Department of Twin Research & Genetic Epidemiology point out these results reflect associations rather than causality but they still suggest this link may be due to polyphenols; a chemical in red wine.

The research looked at the influence of beer, cider, red wine, white wine and spirits on the gut microbiome (GM) and subsequent health in a group of 916 female twins in the UK.

They found that the GM of red wine drinkers was more diverse compared to non-red wine drinkers. This was not observed with white wine, beer or spirits consumption.

These results continued even after the authors took into account factors such as age, weight, the regular diet and socioeconomic status.

They were also able to largely replicate the findings across three different cohorts in the UK, the U.S. And the Netherlands.

The authors themselves note that sorting out any causal effects would require a randomised trial. However, the use of a twin cohort removed many of the confounds and the replication of findings across cohorts also adds weight to their findings.

First author of the study, Dr. Caroline Le Roy from King's College London said: "While we have long known of the unexplained benefits of red wine on heart health, this study shows that moderate red wine consumption is associated with greater diversity and a healthier gut microbiota that partly explain its long debated beneficial effects on health."​

The authors believe the main reason for the association is due to the many polyphenols in red wine. Polyphenols are defence chemicals naturally present in many fruits and vegetables and mainly act as a fuel for the microbes present in our system.

Lead author Professor Tim Spector said: "This is one of the largest ever studies to explore the effects of red wine in the guts of nearly three thousand people in three different countries and provides insights that the high levels of polyphenols in the grape skin could be responsible for much of the controversial health benefits when used in moderation.​

"Although we observed an association between red wine consumption and the gut microbiota diversity, drinking red wine rarely, such as once every two weeks, seems to be enough to observe an effect. ​

"If you must choose one alcoholic drink today, red wine is the one to pick as it seems to potentially exert a beneficial effect on you and your gut microbes, which in turn may also help weight and risk of heart disease. However, it is still advised to consume alcohol with moderation,"​ added Dr. Le Roy.